removed from the rest of the PV system. The disconnects have specific
requirements concerning location, including:
Easy accessibility—with no locked compartments, no building materials
blocking access, and no need for ladders
Location of the service entrance disconnect outside the dwelling
Location of the main PV disconnect elsewhere than in bathrooms or in
the attic
Equipment Disconnects
All PV system equipment should have disconnect switches.
These switches disengage the equipment from all power
sources. Circuit breakers can be used as disconnecting
mechanisms.
Equipment disconnects should comply with NEC Article
690.17. Standalone PV systems require two disconnects—one
switch to disengage the PV array and a second to sever con-
nections with the battery. Large grid-tied PV systems require means to disconnect
many parts, including:
String disconnect switches
Disconnects for sub-arrays
AC output disconnects for every inverter
Entire PV system AC disconnect
Battery Disconnect
For standalone PV systems, disconnecting the battery requires
special attention. Use ganged multipole circuit breakers or
ganged fused disconnects to lessen the likelihood of decreasing
battery life. Ganged fused disconnects may be used when you
plan to run the loads with a connection to the PV array. Use
ganged multipole switches and circuit breakers if the PV
power system is designed to shut down quickly. Ganged multipole switches and
circuit breakers require only a few switch actions.
Charge Controller Disconnects
The NEC expects charge controllers to have the following:
Overcurrent protection
Disconnects
NOTE
According to NEC Article 690.31(E),
circuits can be installed within
a dwelling if a metal raceway
encapsulates the conductors. The metal
conduit/raceway does not burn, and it is
difficult to cut.
TECH TIPS
Circuit breakers may function as a
disconnect. They may also be used as
an overcurrent device. They must be
located appropriately and used within
their accepted ratings.
200 ADVANCED PHOTOVOLTAIC INSTALLATIONS
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